PROJECT SUMMARY/ABSTRACT: Hispanic women have the highest estimated lifetime risk of developing diabetes of all ethnic/gender groups in the US, and their prevalence rates of overweight and obesity are among the highest in the US. Currently, nearly 90% of Hispanic women aged 40-59 are overweight or obese. If diagnosed with Type 2 diabetes (T2D) at age 40, Hispanic women are projected to lose 12.4 life-years, and 21.5 quality-adjusted life-years. Several clinical trials have produced compelling evidence demonstrating the benefits of weight-loss interventions for both diabetic and pre-diabetic individuals, but most of the successful interventions tested in large clinical trials have been too costly for implementation in community settings, and they have not been assessed under real life conditions, targeting vulnerable populations. This pragmatic randomized clinical trial will assess the efficacy, cost, and sustainability of a culturally tailored weight-loss program targeting obese Hispanic women with pre-diabetes or T2D. The intervention will be integrated into patient care at a Federally Qualified Health Center serving over 30,000 low-income patients, and will be delivered by trained clinic staff, with minimal support from research staff. After the effectiveness clinical trial, two cohorts of clinic patients will receive the intervention in a sustainability test. This study builds on our success with a culturally-tailored weight-loss intervention designed for Hispanic women. Elements of cultural adaptation will include: women-only groups, skill-building tasks around food measurement, focus on traditional dietary habits and cultural norms regulating food preparation and consumption, interactive learning formats with a minimum of written materials, culturally congruent physical activity, and addressing acculturative concerns. Follow-up data, including change in weight, waist circumference, and diabetes outcomes, will be collected at 6-, 12-, and 18-months post randomization. Additional analyses will include the cost of delivering the intervention and assessing the intervention's sustainability. The results of this study will inform the development of interventions to prevent diabetes onset or manage T2D in this population.